Embodied carbon of concrete in buildings, Part 1: analysis of published EPD

Abstract

Cement is responsible for 7% of global greenhouse gas emissions, and is predicted to grow with increasing development. The majority is used in concrete, globally the most common material in buildings. Reducing emissions from the use of cement and concrete in buildings is therefore critical in order to limit global warming. However there remain multiple gaps in knowledge about the extent of these emissions. This paper is the first output of a project that aims to understand better the embodied impacts from the use of concrete in buildings, in order to inform and advise policy-makers and industry practitioners, and to provide clear evidence for the path forwards. In order to do so, the project collates, analyses and critiques evidence from multiple sources, reported over three papers. This first paper focuses on the basic data on materials impacts. Over the last few years, several hundred individual Environmental Product Declarations (EPD) have been published for cements, aggregates and concrete mixes, but no publication offers a comparison or overview. Therefore understanding the range and opportunities for the reduction of impacts from concrete remains very limited. This paper provides the first detailed analysis of the EPD for concrete and its constituents. Practice relevance The graphs developed in this paper can be used by designers and manufacturers to understand and reduce the impacts from cement and concrete. Designers will have a better idea of an appropriate coefficient to use at the early design stage before more details are known. As the design progresses, they will be able to use the graphs presented to choose a lower impact cement or concrete with the same performance, as well as to check the likely validity of any EPD. The graphs also provide an incentive to manufacturers to reduce impacts, since they will now be able to compare their products with others. Finally, for those involved in producing EPD, the paper demonstrates the necessity of more detailed rules for consistency, and in the meantime the necessity of full transparency in EPD reports.

Retention not demolition: how heritage thinking can inform carbon reduction

“…33 The standards include a methodology for Environmental Product Declarations (EPD) for construction materials and have led to these being produced by manufacturers in rapidly increasing numbers. 34 Ibn-Mohammed et al argued that embodied emissions were likely to become key metrics that will need to be addressed when considering the whole-life sustainability of a building, and it looks as if this was a prescient observation. 35 Policy has been slow to follow academic research in its interest in embodied emissions, but there are clear signs that this is changing in some nations.…”

The role of carbon metrics in supporting built-environment professionals

“…In later design stages, product-and manufacturer-specific EPDs can be used as source of information. For a deeper analysis of published EPDs, see Anderson & Moncaster (2020). A key task will be to further reduce the GHG emissions associated with the manufacture, use and disposal of their products.…”

Embodied carbon, embodied energy and renewable energy: a review of environmental product declarations

“…Other researchers have reviewed EPD to consider the variation in embodied carbon of stone wool insulation (Silvestre et al, (2015)), glass wool insulation (Hodková and Lasvaux, (2012)) and cement, bricks, wooden-based materials, steel, gypsum plasterboard, glass-wool slabs, stone-wool slabs and ceramic tiles (Ganassali et al, (2018)), but these studies did not consider the relationship with primary energy or secondary fuel use. Anderson & Moncaster, (2020) explored the relationship of embodied carbon (A1-A3) and non-renewable primary energy use and secondary fuel use reported per tonne in EPD for cements but did not look at renewable primary energy. Anderson & Moncaster, (2020) also reviewed the embodied carbon (A1-A3) of in-situ concretes reported in EPD but did not consider their energy use.…”

“…Anderson & Moncaster, (2020) explored the relationship of embodied carbon (A1-A3) and non-renewable primary energy use and secondary fuel use reported per tonne in EPD for cements but did not look at renewable primary energy. Anderson & Moncaster, (2020) also reviewed the embodied carbon (A1-A3) of in-situ concretes reported in EPD but did not consider their energy use. Rasmussen et al, (2021) reviewed the correlation between embodied carbon (A1-A3) and the total use of renewable primary energy (PERT), and of non-renewable primary energy (PENRT) as reported in EPD for structural timber products (cross laminated timber (CLT), glulam, laminated veneer lumber (LVL) and sawn timber).…”